zsteelman Posted October 13, 2011 Share Posted October 13, 2011 I have been having a constant battle with this car to get it into reliable driving condition. It was running decent early spring then sat over the summer and has developed what seems to be a fuel problem. Problem: During low rpms (0-2000) there is considerable hesitation and lean popping in the intake. New fuel filter pre-pump and in the engine bay. Cleaned all hardlines. All new EFI fuel hose throughout entire car. New FPR. In-line EFI fuel pressure guage - reads 30-35 constant. 6 new injectors. 6 new injector electrical plugs, soldered into lines. New NGK plugs. New sparkplug wires. New ACCEL ignition coil. Ran Seafoam through intake twice. Fuel Injector and Fuel system cleaner a few times. Timing is set to 10 degrees. Removed throttle body and cleaned thoroughly. Replaced PCV valve. Checked for vacuum leaks with starter fluid. I checked the AFM initially via the EFI guide and things looked fine but I still feel that there may be something wrong. As you can see in the video it has been opened before and resealed with red RTV. Makes me wonder if someone messed with the tension of the spring within. Any ideas are welcome and appreciated! Quote Link to comment Share on other sites More sharing options...
roger.svoboda Posted October 16, 2011 Share Posted October 16, 2011 might help to know year and turbo or n/a Quote Link to comment Share on other sites More sharing options...
zsteelman Posted October 17, 2011 Author Share Posted October 17, 2011 Sorry bout that, it is a 77 280z. I played around some with the AFM and made it alittle more rich, this seemed to help alot in the low end. However, after the car running for an hour it started to drop fuel pressure at about 1psi a minute until it died. I have come down to the conclusion that it is the fuel pump going out on me once it gets heated up. Before I run out and buy a walbro 255 I am going to rewire the pump with 10g wire and a relay to see if it is the pump itself going out or some wiring issue due to amperage heating up the wire. I currently only get 9v to the factory fuel pump from a cold start, have yet to catch it when it is dieing on me to see the hot range. Any other ideas of what could be causing this leaning issue? From the drop in fuel pressure I am assuming it has to be pump related at this point. Quote Link to comment Share on other sites More sharing options...
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